are generally designed with one needle roller and cage assembly – except wide sizes, which incorpor­ate two needle roller and cage assemblies immediately adjacent to each other, with a lubrication hole in the outer ring (fig. 4).

Full complement drawn cup needle roller bearings are supplied with a special grease to secure the rollers during transport. However, SKF recommends relubricating after mount­ing. Depending on the required grade, SKF recommends SKF LGEP 2 or SKF LGWM 1 grease for relu­brication. The technical specifications of the initial grease fill and the relubrication greases are listed in table 1.

Sealed bearings

For applications where a sufficiently effective seal is not available, or cannot be used for space reasons, SKF supplies certain drawn cup needle roller bearings as sealed bearings. The assortment includes:

These integral contact seals are made of PUR, FKM or NBR. Sealed drawn cup needle roller bearings are, under normal conditions and with appropriate counterface, an extremely cost-effective solution to exclude solid contaminants and moisture, and retain the lubricant in the bearing.

When capped bearings must operate under certain conditions, such as very high speeds or high temperatures, some grease may leak. For bearing arrangements where this would be detrimental, appropriate actions could be taken.

Drawn cup needle roller bearings with one or two seals are supplied greased. They are filled with high-quality grease (table 2) under clean conditions.

The relatively large quantity of grease in the bearings means they can be operated for long periods before relubrication is required (→ Perform calculations). SKF recommends SKF LGWA 2 grease (table 2), if relubrication is required.